diff --git a/lib/internal/mime.js b/lib/internal/mime.js
index 0a1d8e7e67916b..07d80a72625cac 100644
--- a/lib/internal/mime.js
+++ b/lib/internal/mime.js
@@ -70,7 +70,7 @@ function parseTypeAndSubtype(str) {
   const invalidSubtypeIndex = SafeStringPrototypeSearch(trimmedSubtype,
                                                         NOT_HTTP_TOKEN_CODE_POINT);
   if (trimmedSubtype === '' || invalidSubtypeIndex !== -1) {
-    throw new ERR_INVALID_MIME_SYNTAX('subtype', str, trimmedSubtype);
+    throw new ERR_INVALID_MIME_SYNTAX('subtype', str, invalidSubtypeIndex);
   }
   const subtype = toASCIILower(trimmedSubtype);
   return [